Non-stalling gasoline fuel compositions



U d States Patent 2,948,596 NON-STALLING GAsoLiNE FUEL COMPOSITIONS Henry A. Ambrose, Penn Township, Allegheny County,

I and Gardner E. Gaston, Tarentum, Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware NO Drawing. Filed Dec. 20, 1955, Sel. No. 554,142

4 Claims. c1. 4458) This invention relates to non-stalling gasoline fuel compositions that are adapted to improve the Operation of internal combustion engines under cool, humid atmos' pheric conditions. More particularly, the invention relates to gasoline fuel compositions that contain a small amount, sufiicient to reduce the tendencies of the composition to promote stalling in an internal combustion engine of the spark ignition, reciprocating type, of a salt of a dialkyl sulfosuccinic acid.

When an internal combustion engine is operated under cool, humid atmospheric conditions, using a gasoline fuel having a relatively loW 50 percent ASTM distillation point, excessive engine stalling is apt to be encountered at idling speeds during the warm-up period, especially where engine idling Occurs following a period of light load operation. Engine stalling under such conditions has been attributed to the partial or complete blocking of the narrow air passage that exists between the carburetor throat and the carburetor throttle valve during engine ilding, by ice particles and/ or solid hydrocarbon hydrates that deposit upon and adhere to the metal surfaces of the carburetor parts. Such icing of carburetor parts occurs as a result of the condensation of moisture from the air drawn into the carburetor and as a result of the solidification of such condensed moisture. The aforesaid condensation and solidification of moisture are caused by the refrigerating effect of rapidly evaporating gasoline. cordingly, excessive engine stalling due to carburetor icing occurs as a practical matter only in the, instance of gasolines containing a large proportion of relatively highly volatile components.

Excessive engine stalling is, of course, a source of annoyance owing to the resulting increased fuel consumption, battery wear and inconvenience offrequent restart ing. It is therefore important that the inherent engine stalling characteristics of gasoline fuels be reduced substantially, where the 50 percent ASTM distillation point of such gasoline fuels is sufliciently low to cause a problem in this respect. I

We have found that the stalling characteristics of gasoline fuel compositions having a 50 percent ASTM distillation point below about 220 F. and that normally tend to promote engine stalling due to carburetor icing are markedly improved by the incorporation therein of -a small amount of a member selected from the group consisting of alkali metal, alkaline earth metal, ammonium, and ethylolamrnonium dialkyl sulfosuccinates, the alkyl groups of which each contain 7 to 9 carbon atoms, at least 6 of which are in a straight chain, but there being no group containing more than 7 carbon atoms attached to the alpha carbon atom of said alkyl groups. In one embodiment of the invention the gasoline composition also contains about 0.25 to about 0.75 percent by volume of the composition of a light lubricating .oil having a viscosity. at 100 F. of about 50 to about500 Saybolt Universal seconds. 7 V p The dialkyl sulfosuccinate anti-stalling agents disclosed herein can be chanacterized as polar, surface-active materials. While the invention is not limited to any theory of operation, it might appear that the polarity of the disclosed agents tends to cause orientation of the latter upon the metal surfaces of the throttle valve and other critical carburetor parts'conta'cted by the gasoline composition, thus forming a moisture-displacing, residual coating on said carburetor parts, which coating tends to prevent the adherence to said metal surfaces of accumulations of ice of magnitudes sufiicient to block the narrow air passages that exist in carburetor throats at engine idling conditions.

It is also considered that the dialkyl sulfosuccinates may orient themselves about small individual water or ice particles, thus tending to prevent the formation of macrocrystals of ice of a size suificient to block carburetor air j passages at engine idling'conditions. Although the eifectiveness of the herein disclosed addition agents is believed to be' attributable at least in part to the polar ch-aracteristics thereof, this general explanation is somewhat negatived by the fact that many oil-soluble polar agents have little or no effect upon engine stalling due to carburetor icing. 7 When the herein disclosed dialkyl sulfosuccinate antistalling agents are utilized in gasoline compositions that,

contain a small amount of a light lubricating oil, it might appear that the dialkyl sulfosuccinates, by virtue of their aifinity for the lubricating oil, tend to attract the oil to the same critical carburetor surfaces referred to above, while simultaneously increasing the spreading and metal wetting characteristics of the oil, thus promoting the formation of an adherent oil film on the metal surfaces of the carburetor'parts. The oil film therefore would appear to function similarly asthe dialkyl sulfosuccinates, but the superior metal wetting properties imparted to the oil by the additives are believed to enable the oil to displace, moisture from metal carburetor surfaces that it would.

not thoroughly displace alone.

The preparation of the dialkyl sulfosuccinates disclosed As indicated above, the present invention includes the' use of alkali metal, alkaline earth metal, ammonium, and 'ethylolammonium salts of a particular class'of dialkyl sulfosuccinic acids. This class of salts can be represented by the. general formula:

[Elii-soilz boon boon where C, H, O and S are respectively carbon, hydrogen,-

oxygen and sulfur; Where R is an alkyl group containing 7 to 9 carbon'atoms, at least 6 of which are in a straightv chain, there being no group attached to the alpha carbon atom of said alkyl groups containing more than 7 carbon atoms; where Z is a salt-forming group selected from' the class consisting of alkali metal, alkaline earth metal,

ammonium and ethylolammonium; and Where n is an integer equal to the valence of Z. In the foregoing general formula, R can represent identical or different alkyl groups of the type specified above.

Especially effective results are obtained by the use ofalkali metal dialkyl sulfosuccinates wherein the alkyl groups are branched and contain 8 carbon atoms, since the surface-active properties of such compounds appear to be less affected by low temperatures. An example of adialkyl sulfosuccinate'with which excellent results have a j Patented Aug. 9, 1960 3 been obtained is the sodium salt of di-(2-ethylhexyl) sulfosuccinic acid, the formula of which is:

where Na is sodium and C, H, O, and S are as indicated above.

Examples of other dialkyl sulfosuccinates, the nse of which is included by this invention, are the sodium, potassium, calcium, barinm, ammonium and triethylolarnnioniurn salts of di-(n-heptyl), di-(n-octyl), di-(l-rnethylhegryD-sec, di-(l-butylamyn-sec, di-(isobutyl 3 methylbii tylj-sec, di-(2-ethylhexyl-)-sec, di (l-methylheptyhsec, and di -(1-methyl 45 ethylhexyD-sec sulfosuccinic acids. Examples of salts of mixed esters that are suitable for the purposes of this invention are the sodium, potassium, calcium, barium, ammonium and triethylolammonium salts of mono-Z-ethylhexyl, mono-l-methyl- 4 et hylhexyl sulfosuccinic acid, and mono-2-ethylhexyl, mono-l-methylheptyl sulfosuccinic acid.

The class bf dia'lkyl sulfosuecinates included by this invention possess a substantially similar balance of surface-active properties, as a result of which they are rendered suitable for the purposes of this invention. The similarity in the surface-active properties of the dialkyl sul fosuccinates included in the scope of this invention is evidenced by the fact that the class of compounds dis: closed exhibit relatively low water solubility and unusuallow Draves wetting power values. In general, the Draves wetting power value for the class of dialkyl sulfosuccinates included by the invention will not substantially ex ceed about 0.5 while the preferred class of mateirials will exhibit Draves wetting power values between about 0.15 and about 0.25. In'contrast, dialkyl sulfohooihatso W ose a k l groups and o l ta i groups e other th s ned herein i l e h b r os wet in powe values ubs ial n e c s o m m in indicated above, and they will also normally extsti ta ia ea er solubility n rt t s n o st d of cou se, that the foregoing discussion is not -sen n ended o su any dir c o noot otween water solubility or wetting power and anti-stalling hr ot o Rather. t is in end d mer l o ind ca r. era ba an e of s r e-fish o or oh l heo ass o com ounds o solosotl oroih as he oo fi D v s e n PW 17 alues i n above refer to' the number of per liter required to give a 25 second sinking time bythe Draves test at 30 C. The Draves test is a conventional test for determining wetting power.

The dialkyl sulfosuccinate anti-stalling agents described herein are useful when incorporated in gasoline compositions of the type disclosed in an amount sufiicient to reduce the engine stalling characteristics thereof. For ex? ample, an improvement in the stalling characteristics of gasolines of the type disclosed will normally be obtained by the addition thereto of the herein disclosed dialkyl sulfosuccinates in amounts of at least 0.001 percent by Wfiight of the composition, i.e about 3 pounds per housand barrels of gasoline. For fully effective results, the dialkyl sulfosuccinate antirstalling agents disclosed hereinwill be employed in proportions of at least about 0, 05 percent by weight of the composition, i.e,, about 15 pounds per thousand barrels of gasoline. Excellent r e. sal h ve be ob a d y the d i ion of a diallty solios ooi ato o the k d disoloso he o s oliho oomr s h n P o ns ho woo 5 a d 50 oun s er th sass! hote o asol ne an hi nsti utes ho err oohoo re ion tan o for he Pur os s o is ave Howe er. la ge Pro ortions oat! he use In most instances the concentration of the herein disclosed anti-stalling agents need not exceed about 0.1 percent by weight of the composition, even in instances of gasolines having severe engine stalling tendencies.

It will be appreciated that the optimum concentration of the disclosed dialkyl sulfosuccjnate anti-stalling agents can vary within the disclosed range according to the parv tieular gasoline employed, since the problem of engine stalling due to carburetor icing is a function of the 50 percent ASTM distillation point of the gasoline. Thus, greater concentrations of the additive are normally desirable with decreasing 50 percent ASTM distillation point. The optimum concentration of the dialkyl sulfosuccinate anti-stalling agents can also vary somewhat according to the particular make and rnodel of engine in which the gasoline is used and also according to the severity of the atmospheric conditions encountered. With regard to the last mentioned factor, the problem of engine stalling due to carburetor icing resulting from the refrigeration by evaporating gasoline of moisture condensed from the atmosphere has been observed to be significant at temperatures between about 30 and 50* F., erg, 35, 40-, 45, 50- E, and-when the relative humidity is in excess of about 65 percent, e.g., 75, 85, 99 percent. The optimum concentration of the dialkyl sulfosuccinate anti-stalling agents will be one that is sufficient to effect a substantial reduction in the stalling tendencies of the fuel at the atmospheric conditions of temperature and humidity which are likely to be encountered in service.

Practically speaking, the problem of engine stalling due to carburetor icing caused by rapid evaporation of gasoline occnrs only in connection with gasolines having a 50 percent ASTM distillation point of not greater than about 235 F. While occasional engine stalling may occur as a result of carburetor icing at severe atmospheric conditions of temperature and humidity with gasolines having somewhathigher 50 percent ASTM distillation points, experience has indicated that the problem does not assume major importance except with gasolines of the character indicated. The problem of engine stalling due to carburetor icing is especially severe in conriection with gasolines having a 50 percent ASTM distillation pointof less than about 220 F. The invention is particnlarly useful in connection with such gasolines. The term gasoline is used herein in its conventional senseto include hydrocarbon mixtures having a 9 P r nt. ASTM sti lat on point f not more than. about 392 F. and a 10 percent ASTM distillation point o ot mor t n abou 1.

As Prev ou ndic ted. e asol ne oompositions of hi. nv nt on ar h tionally be fit d i e pec to ion-sta in ohs 'ao o is h he nolhs oa er n of a mall amoun of a u ricatin l havin a viscosity at 00 otb t en about 50 nd b h 500 yh Uni e s l seconds; f r example n o ha in soosity of about 1 00 S.U./ F. can be nsed with advan Althou h i hl P a hi lubricating tillates can be used, lubrica ing distillates obtained from Coastal or naphthenic type crude petroleum oils are preferred because of their superior solvent properties. The lubricating oils utilizedin' the gasoline compositions of this invention can have been solvent-treated, acid-treated o o h r iso ofih d Prio o incorporation n o the soline, compositions of this invention. The lubricating dis l ate efer e t a hso ul' the aso e omp sitions of thisinvention in amounts of from about 0.25 oahout 0-75 P r nt by vo um o h c i on for exam l 0-5 o me erc n n su o o h io s se lubr ca dis i tes nd to i t t e n al n inaction of the diallsyl sulfosuccinates and in addition function as cleansing solvents and as upper cylinder and valve top lubricants. Greater amounts of lubricating oil can be used but without appreciable further improvemom he sta in toadoao os o h as line omp tio; howsysr hl... 1?! o shrioe iti o l. e should not-be so great as to adversely affect the, volatilityand combustion characteristics of the ultimate gasoline com-g positions. 7 V s The dialkyl vsulfosuccinate anti-stalling agents of this invention can be incorporated into the base gasoline fuel compositions in any suitable manner. Thus, they can be added as such to gasoline or in the form of a dispersion or solution in solvents such as butanol, .isopropanol, ethanol, methanol, 2-butoxyethanol, diethylene glycol monobutyl ether, benzene, toluene, heptane, kerosene, gasoline, mineral oil or the like, which solvents may or may not themselves additionally contribute to the anti-stalling characteristics of the ultimate composition. If, desired, the disclosed dialkyl sulfosuccinate anti-stalling agents can be incorporated in gasoline fuel compositions in admixture-with other materials designed to improve one or more properties of the gasoline such as antioxidants, antigumming agents, anti-knock agents, e.g., tetraethyl lead, lead scavenging agents, e.g., ethylene dibromide, ignition control additives, de-icing agents, corrosion inhibitors, dyes and the like. 7

Gasoline compositions of this invention-can be further illustrated by the following representative specific examples.

EXAMPLE I A motor gasoline composition according to this invention and having reduced engine stalling tendencies was prepared by incorporating sodium di-(Z-ethylhexyl) sulfosuccinate, in the proportion of 15 pounds Per thousand barrels, in a sample of motor gasoline having a strong tendency as such to promote engine stalling due to carburetor icing. The base gasoline employed in this example was a blend containing 12 parts by volume of a light thermally cracked gasoline distillate and 100 parts by volume of a gasoline distillate having the following inspections:

The blended gasoline had a 50 percent distillation point of 200 F.

EXAMPLE II An additional motor gasoline composition in accordance with this invention and having reduced engine stalling characteristics was prepared by admixture of sodium di-(Z-ethylhexyl) sulfosuccinate, in the proportion of 15 pounds per thousand barrels of gasoline, with the blended base gasoline described in Example I, to which there was also added 0.5 percent by volume of an approximately 100 S.U.S./ 100 F. Texas (Coastal) lubricating distillate, a sample of which had the following inspections:

Gravity, API 24.5 Viscosity, SUV, sec.:

70 F..- 235 100 F 106 130 F 63.9 210 F 38.3 Viscosity index l6 Pour, F 60 Carbon residue, Conradson, percent 0.02

The foregoing specific embodiments of the compositions of this invention are illustrative, and other suitable compositions within the scope ofthis invention and having satisfactory anti-stalling characteristics can be prepared similarly by the substitution in the foregoing examples of other gasolines of the type disclosed herein and by the incorporation therein of the same orequivalent proporof Example I 50 pounds, per thousand barrels of gasoline,

of thesodium, potassium, calcium, barium, ammonium and triethylolammonium salts of di-(n-heptyl), di-(noctyl), di-(l-methylhexyD-sec, di-(l-butylamyl)-sec, di- (isobutyl-3-methylbutyl)-sec, di-(2-ethylhexyl)-sec, di-(l-' methylheptyl)-sec, and di-(1-methy1-4-ethylhexyl)-sec sulfosuccinic acids.

As heretofore indicated, the dialkyl sulfosuccinate anti stalling agents of this invention produce an appreciable improvement in the stalling chanacteristics of gasolines that normally promote engine stalling due to carburetor icing. To illustrate the nature of the improvement obtained, in the table following there are presented illustrative results obtained with engine tests using a gasoline fuel composition prepared in accordance, with this invention. For purposes of comparison there are also presented in the table below the results obtained with engine tests carried out on a sample of the uninhibited test gasoline.

According to the test procedure followed the fuel compositions to be tested were fed to a standard, 216 cubic inch displacement, 6-cylinder overhead valve Chevrolet engine, the air supply to the carburetor of the engine being obtained by natural aspiration from a cold room atmosphere. The engine was equipped with astandard Carter downdraft carburetor. The ambient temperature of the cold room was 40 F., and the relative humidity was to percent.

The first operating cycle of the engine included, after permitting the engine to cool to the ambient temperature of 40 F., starting the engine and running for 40 seconds at 2000 r.p.m. and then for 20 seconds at 500 r.p.m. (idle) under no load, or until the engine stalls. Repetition of the foregoing cycle 20 times constituted one test.

From the results presented in the foregoing table it will be seen that uninhibited gasolines having a 50 percent ASTM distillation point in the range disclosed possessed poor stalling characteristics. In tests of other uninhibited base fuels it was found that a gasoline having a 50 percent A-STM distillation point of 230 F. produced an average (7 tests) of 1.4 stalls, whereas a gasoline having a 50 percent ASTM distillation point of 240 F. produced an average (19 tests) number of stalls approaching zero. From the data in the foregoing table it is also apparent that gasolines having a 50 percent ASTM distillation point within the range disclosed herein will be markedly improved by incorporation therein of the herein disclosed proportions of the dialkyl sulfiosuccinate ti-stal in a ents Qt this in m z T th a lin u om o i ion Qt th n ati n.

there can also be added one or more add iqntl l additive n s si d o m e one or mo racterist cs of h ga ol n el- F r e amh e n ox ants, at knock agents, ignition control agents, otherdeicing agents, anti-rust agents, dyes, lead scavenging agents, antiigumm e s and he ike n b a ed to he qmpositions of this invention, and the invention specifically includes gasoline compositions containing such additives.

Numerous additional embodiments of the invention will readily suggest themselves to those skilled in the art. Accordingly, we do not intend to be limited by the tore. going description, but only by the terms of the claims appended hereto.

We claim:

1. A gasoline fuel composition comprising a major amount of a hydrocarbon mixture that boils in the gaso; line range, that has a 50 percent ASTM distillation point not greater than about 220 E. and that normally tends to promote stalling of internal combustion engines, and containing a combination of (a) 0.001 to about 0.1 percent by weight of the composition of a member selected from the up on i t n of lka metal, a kal ne ea metal, ammonium and ethylol ammonium salts oi dialhyl sulfosuccinic acids, the alkyl groups of which each contain 7 to 9 carbon atoms, at least 6 of which are in a straight chain, no group attached to the alpha carbon atom of said alkyl groups containing more than 7 carhon atoms, and (b) about 0.25 to about 0.75 percent by volume of the composition of a light lubricating oil having a viscosity at 100 F. of about 50 to about 500 S.U.S., the amount of said combination being 'sufiicient to reduce the engine stalling characteristics of the gasoline composition.

2. A gasoline fuel composition comprising a major amount of a hydrocarbon mixture that boils in the gasoline range, that has a 50 percent ASTM distillation point not greater than about 220 F. and that normally tends to promote stalling of internal combustion engines, and containing a combination of (a) to 50 pounds, per thousand barrels of said hydrocarbon mixture, of sodium di- (2-ethylhexyl) sulfosuccinate, and (b) about 0.25 to about 0.75 percent by volume of the composition of a light lubricating oil having a viscosity at 100 F. ofabout 50 to about 500 S.U.S., the amount of said combination f 0 and sod m di-lkth hexy s l uc a e b n f ic ent o re ce he n ine s alli cha ac eris ics o the gasoline composition. 7

A as l n l compo itio cqmp ne a majo mm t of a h dr c rb n. m xtur hat bq n he sol ne range, t a h a ercent ASTM d stilla i n ain no re h n b ut 22 n ha n rmall e ds o P om e ta l of in na m usti a en in and, ca eit ig a mb nat n f (a) ab ut 15 p nds p h il and ar els f d hYd QQaIbQ m xtur at sodium sli- -c h bexy s lfesu'c aate and a ou .15 e cent by ume of a i ht lubrica n Q l having iss s t alt-1 .9 F- of bo 59 t9 Q Qm S 'O -U-S', he amqan of aid combinatiqa o oil. and. so i m y yl) fpsu ci 1e hsinssufl en 9 re u the engine s ail fi a is ic 9 th gasqliae mp sit oa- A aasa ine met r ti e! c r si n maintai s j r mount o a m lar a c ias hat as a 5 ercen AS M stillatisg iat 39i e t than ab ut 220 F- nd tha e mall tends to animate sta l n of auto iqtive internal combustion engines, and containing a combinan f (a) 5 to 50. poun s per thousand bar els. 0 gasoline f um di t lsultcs na e, d abou 0.25 to about 0.75 percent by volume of the composition of a light lubricating oil ha ing a viscosity at F,

of about 50 to about 500 S;U.S.,'the amount of said combination of oil and sodium dioctylsulfosuccinate being sufficient to reduce the engine stalling characteristics of the gasoline composition.

References Cited in the file of this patent UNITE}; STATES PATENTS.

OTHER REFERENCES Aviation Gasoline Manufacture, by Van Whihle, McGraw-Hill C0., N.Y., 1944, First Ed, pp. 16 and 17.

ASTIfM Standards on Petroleum"l roducts and Lubricants, American Society for Testing Materials, November 1955, p. 370. 

1. A GASOLINE FUEL COMPOSITION COMPRISING A MAJOR AMOUNT OF A HYDROCARBON MIXTURE THAT BOILS IN THE GASOLINE RANGE, THAT HAS A 50 PERCENT ASTM DISTILLATION POINT NOT GREATER THAN ABOUT 220*F. AND THAT NORMALLY TENDS TO PROMOTE STALLING OF INTERNAL COMBUSTION ENGINES, AND CONTAINING A COMBINATION OF (A) 0.001 TO ABOUT 0.1 PERCENT BY WEIGHT OF THE COMPOSITION OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL, ALKALINE EARTH METAL, AMMONIUM AND ETHYOL AMMONIUM SALTS OF DIALKYL SULFOSUCCINIC ACIDS, THE ALKYL GROUPS OF WHICH EACH CONTAIN 7 TO 9 CARBON ATOMS, AT LEAST 6 OF WHICH ARE IN A STRAIGHT CHAIN, NO GROUP ATTACHED TO THE ALPHA CARBON ATOM OF SAID ALKYL GROUPS CONTAINING MORE THAN 7 CARBON ATOMS AND (B) ABOUT 0.25 TO ABOUT 0.75 PERCENT BY VOLUME OF THE COMPOSITION OF A LIGHT LUBRICATING OIL HAVING A VISCOSITY AT 100*F. OF ABOUT 50 TO ABOUT 500 S.U.S., THE AMOUNT OF SAID COMBINATION BEING SUFFICIENT TO REDUCE THE ENGINE STALLING CHARACTERISTICS OF THE GASOLINE COMPOSITION. 